Cotton - Aphids
Small insects, pear shaped, with long antennae, almost transparent, 1*2 mm in length, color green, greenish grey, dark green or blackish brown. Most have no wings. Winged forms (alatae) are usually black.
Heavy infestations cause curling or crinkling of leaves. Aphids feed on the youngest, tenderest growth and, when present in large numbers, may completely cover the terminal parts of the plants they infest. During the peak period of blooming, aphids may cause older leaves to turn yellow and shed. Severe infestations can cause heavy yield/quality losses.
Generation time is only a few days. Females produce offspring without mating (parthenogenesis) and give birth to living young (viviparous) quickly developing into small nymphal colonies on the underside of leaves (esp. young leaves).
These nymphs pass through four development stages, within one week, to become adults which then produce further colonies of nymphs. Aphids migrate into cotton fields as winged adult females. Adults can live for 2-3 weeks and produce two or more offspring each day.